Presently, there are just two methods generally used in the art of locating and making holes in structural shapes, plates and non-round tubes. First there are stationary machines available that can locate and drill holes, and others that can locate and punch holes in structural shapes, but are not practical for use on plates or non-round tubes, most of these machines are equipped with numerical controls and electronic measuring devices. In comparison to my invention, these machines are expensive, massive, require foundations, conveyors, special holding devices, and frequent maintenance. The second method is the age-old practice of using hand held measuring tapes, squares and chalk lines to locate by laying out in two directions every hole specified. These locations must then be center punched, and in some cases, both a center punch mark and a pilot hole are necessary before the desired final hole diameter can be drilled or punched. This method requires the employment of highly skilled mechanics and limits the drilling or punching of just one hole at a time. My invention has the ability to drill two holes simultaneously.
In comparison to the first method, my invention is very inexpensive and requires very little maintenance. It allows for drilling in the shop or field and other than using common dunnage material and shop sawhorses, no special holding devices are necessary.
My invention is a great deal faster and more accurate than the second method and does not require highly skilled mechanics to operate it. In many situations, it can make a considerable savings in material handling.
The following disclosures may be relevant to various aspects of the present invention:
U.S. Pat. No. 3,391,593 Inventor: Jordan Issue Date: Jul. 9, 1968 PA1 U.S. Pat. No. 3,981,605 Inventor: Wirsing Issue Date: Sep. 21, 1976 PA1 U.S. Pat. No. 4,198,181 Inventor: Smelser Issue Date: Apr. 15, 1980 PA1 U.S. Pat. No. 4,753,556 Inventor: Solko Issue Date: Jun. 28, 1988
The relevant portions of the foregoing disclosures may be briefly summarized as follows:
U.S. Pat. No. 3,391,593 describes an apparatus for punching holes in structural shapes. The apparatus has a conveyor of rolls to longitudinally position the shape and the punch is laterally movable on a second set of rollers to accurately position the punch.
U.S. Pat. No. 3,981,605 discloses a tool carrying carriage for movement in both the X and Y axes. There is provided precision ball bearings on precision shafts with cam followers on guide bars to carry the load and minimize deflection of the shafts.
U.S. Pat. No. 4,198,181 describes an apparatus for drilling holes in the web and flange of an H-beam on opposite sides of the web. There is a framework having a first fixedly mounted section and a second vertically movable second section. Vertical and horizontal drills are mounted on the second section of the framework.
U.S. Pat. No. 4,753,556 discloses an apparatus for positioning and clamping a power tool such as a drill onto a workpiece such as a railroad rail.